The invention relates to a motor vehicle door lock or the like, mainly a motor vehicle side door lock, optionally also a motor vehicle rear door lock, rear hatch lock or hood lock, with the features of the preamble of claim 1.
Motor vehicle door locks with auxiliary closing drives have been known for a long time and in the meantime have become common in mid-range vehicles. In particular worm wheel drives are popularly used because they have especially small dimensions. Ordinarily the drive element of the auxiliary closing drive is coupled to the lock latch such that the lock latch can run freely in the pulling direction. This takes into account the fact that vigorous slamming of the motor vehicle door is designed to be able to entrain the lock latch in advance of the drive element.
Normally, in a motorized, especially electric-motorized auxiliary closing drive it is turned on after the lock latch has first reached a preclosing position. The preclosing position is generally the preliminary catch or a position slightly behind the preliminary catch in the pulling direction (overstroke). From there then the lock latch is transferred likewise by motor into the main closing position, generally the main catch on the lock latch. Moving the lock latch by means of the corresponding drive element of the auxiliary closing drive into the main closing position is associated with the problem that when the drive element is stationary in front of the corresponding force transfer surface of the lock latch, the motor vehicle door can be blocked. Even in the closing process itself, therefore when the motor vehicle door is being pulled by means of the auxiliary closing drive, emergency situations can arise, for example, the extremities or articles of clothing can be caught. The approach in the prior art uses mechanical, key-actuated emergency trigger elements (EP-B-0 496 736) or coupling levers which can be raised manually from the outside opening handle (DE-A-38 36 771).
In the known motor vehicle door lock or the like which underlies the invention (DE-A-197 14 992) there is a decoupling possibility for the auxiliary closing drive which is suitable for emergency purposes and which does not require mechanical action into the lock mechanism from the outside. To do this, in this motor vehicle door lock an electromagnetic clutch is integrated into the step-down gear and it can couple the electric drive motor to the drive element and decouple it therefrom. Even when the electric drive motor is running the meshed electromagnetic clutch can be decoupled depending on a triggering criterion. The preferred triggering criterion is pulling on the outside opening handle (on the inside opening handle), which triggers an electrical switching process which leads to decoupling of the electromagnetic clutch. This corresponds to the intuitive action which arises in purely mechanical motor vehicle door locks in order to open the door quickly again when a coat becomes caught when pulling the motor vehicle door closed.
In the aforementioned prior art (DE-A-197 14 992) it is furthermore explained that as alternatives there could be motor shutoff or reversal of the direction of rotation of the electric drive motor of the auxiliary closing drive based on the triggering criterion.
Reference should be made to DE-A-197 14 992 for the further prior art on this subject and embodiments of the corresponding auxiliary closing drives.
The above explained motor vehicle door lock or the like which forms the starting point for the teaching of the invention is otherwise an electric lock of the modem design in which there is also an electric auxiliary opening drive which is turned on to raise the detent pawl off the main catch or the preliminary catch of the lock latch for purposes of opening the door. The triggering criterion here is likewise pulling on the inside opening handle or on the outside opening handle with the motor vehicle door lock or the like released. In this way the electrical auxiliary opening aid drive is triggered and it then acts on the detent pawl such that the latter is raised. In principle detailed approaches have been known for a long time, among others from DE-A-29 49 319 and DE-A-32 42 527.
For a pure electric lock, therefore a motor vehicle door lock or the like with an electrical auxiliary opening drive, the question of xe2x80x9credundancyxe2x80x9d for an emergency is always important. In many embodiments mechanical redundancies are used. Then the detent pawl in addition to being raised by means of the auxiliary opening drive can also be raised mechanically, for example by a closing cylinder (EP-B-0 496 736). But here too a purely electrically redundant system is already known (DE-A-29 49 319) which is characterized in that in addition to the main battery of the vehicle electrical system, there is an extra battery. The safety-relevant systems and thus especially the electrical auxiliary opening drive of the motor vehicle door lock are supplied from the extra battery as the primary energy source. The extra battery is recharged in a suitable manner simply from the main battery of the vehicle electrical system. Discharging of the extra battery for the safety-relevant systems back into the main battery of the vehicle electrical system is prevented by circuity. This system ensures that even when the power of the vehicle electrical system fails for example after an accident (rupture of cable connections, etc.) the safety-relevant systems which are supplied from the extra battery continue to function. Of course the extra battery as an active element must be continually monitored for its charging state.
The teaching of this invention is to optimize an electrical motor vehicle door lock or the like with an electrical closing aid and electrical opening aid in terms of construction and safety engineering.
The aforementioned object is achieved in a motor vehicle door lock or the like with the features of the preamble of claim 1 by the features of the characterizing part of claim 1. Advantageous embodiments and developments are the subject matter of the dependent claims.
As claimed in the invention, the additional electrical component which are necessary in the purely electrically driven motor vehicle door lock which forms the starting point, specifically the electromagnetic clutch in the drive train of the auxiliary closing drive, is replaced by a mechanical coupling element which can be raised for decoupling. Its actuation takes place using the electrical auxiliary opening drive which is present anyway and which is triggered in one version of actuation such that it lifts this coupling element of the auxiliary closing drive. The previously separate systems, the auxiliary closing drive on the one hand and the opening aid on the other, are therefore linked to one another here by control engineering such that the electrical auxiliary opening drive intervenes into the train of force transfer of the auxiliary closing drive as the emergency actuation. Thus the electrical and circuitry prerequisites in a purely electrically driven motor vehicle door lock or the like are optimally used.
The teaching of the invention becomes especially important in the implementation of active electrical redundancy with an extra battery, as is known from the wider prior art. Here optimization according to the teaching of the invention is achieved by the power supply of the electrical auxiliary closing drive being accomplished not via the recharged extra battery, but directly from the vehicle electrical system. This approach as claimed in the invention takes into account that it is not a good idea to route the considerable current consumed by the auxiliary closing drive via the extra battery. It can easily be drawn directly from the vehicle electrical system without endangering safety. When the vehicle electrical system fails the auxiliary closing drive does not work, but this is only an inconvenience, not a safety hazard. Conversely, the power supply of the auxiliary opening drive which also continues to perform the emergency function for the auxiliary closing drive remains optimum in terms of safety engineering.